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Ru/Ta Alloying Behavior and its Implications for Laminate Based CMOS Integration

Published online by Cambridge University Press:  01 February 2011

Judit G. Lisoni ,
Tom Schram ,
Thomas Witters ,
Nausikaa Van Hoornick ,
Naoki Yamada  and
Stefan De Gendt
Judit G. Lisoni
Affiliation:
schram@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuven, -, B-3001 Heverlee, Belgium
Tom Schram
Affiliation:
schram@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuve n, B-3001 Heverlee, Belgium
Thomas Witters
Affiliation:
witterst@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuven, B-3001 Heverlee, Belgium
Nausikaa Van Hoornick
Affiliation:
nausikaa@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuven, B-3001 Heverlee, Belgium
Naoki Yamada
Affiliation:
yamada@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuven, B-3001 Heverlee, Belgium
Stefan De Gendt
Affiliation:
degendt@imec.be, IMEC, SPDT Div., Kapeldreef 75, Leuven, B-3001 Heverlee, Belgium
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Abstract

The microstructural and electrical characterizations of RuxTa1-x alloys obtained from Ru-Ta laminates are presented. The films were deposited on SiO2 and HfO2 and capped with TiN to avoid oxidation of the top surface. The alloys were attained by post-anneal thermal treatments in the range of 500-1000 °C in Ar atmosphere. Co-sputtered RuxTa1-x alloys were used as references. In particular, Ru0.4Ta0.6 phase could be obtained when the Ru-Ta laminate was annealed at 1000 °C. The alloying reaction is limited either by the tantalum nitride or oxide formation being the source for Nitrogen the TiN capping used on top of the stack and the Oxygen either the dielectric films or the one stuffing the films after exposure to the atmosphere.

Independent of the Ta content a mid gap work function was obtained. Measured WF's in laminate-obtained alloys and alloys themselves differ from other literature data, where a more n-type like WF are measured, and indicating process dependence. In the present study mid-gap or rather p-type work functions were found, 4.5 eV < WF < 4.9 eV.

Keywords

alloyRuTa
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 917: Symposium E – Gate Stack Scaling – Materials Selection, Role of Interfaces, and Reliability Implications , 2006 , 0917-E08-04
Copyright
Copyright © Materials Research Society 2006

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References

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